Our goal is to try to understand how plants regulate their development in response to two important environmental variables, light and temperature. Our work mainly focuses on the flowering process, because it implies the activation of a developmental program triggered by the changes in the light and temperature the plant is exposed to. Plants integrate this environmental information to promote flowering upon arrival of the favorable season. Our main question is how do plants regulate flowering in response to ambient light and temperature at the molecular level? To address this we use Arabidopsis thaliana as a model. It is ideal for the genetic approach. Among other reasons, it is easy to grow a large number of plants in a reduced space, its life cycle is relatively short and it is mainly self-pollinating. Arabidopsis is a long-day plant that flowers in spring when the photoperiod lengthens.